Effects Of Sowing Pattern And Planting Density On Population Construction And Yield Of Winter Wheat

The sowing pattern of winter wheat in Guanzhong region of Shaanxi is relatively simple,and the similar sowing patterns are not conducive to the matching of improved varieties and good patterns and the construction of reasonable population structure of winter wheat.How to choose a reasonable wheat sowing patterns,and whether the appropriate planting density of wheat is the same under different sowing patterns,is still unclear.Based on this,this study selected the winter wheat variety Xinong 538（XN538）with light ear type and Lankao Aizao8（LK8）with heavy panicle type,and two different sowing patterns are adopted:drill seeding（S1）,bunch sowing（S2）,and two different planting density treatments,300×10⁴ plant·hm^-2（D1）,450×10⁴ plant·hm^-2（D2）,constituting a three-factor interaction model,to determine the yield and composition factors,grain quality,population quality,photosynthetic index,lodging index between different treatments.It was used to explore whether the yield of winter wheat could be increased by the method of hole sowing in Guanzhong region of Shaanxi Province,and the suitable planting density of different winter wheat varieties for the patterns of hole sowing.The main conclusions were drawn:1.The yield of different varieties responds inconsistently to the sowing patterns and planting densities.The sowing pattern and planting density had a significant effect on the yield among different treatments mainly by affecting the spike number per hectare and grain number per spike of winter wheat varieties with different panicle types.Under different treatment conditions,the yield of XN538 ranged from 5.75 to 6.54 t·hm^-2,and the yield was the highest under the condition of high-density and bunch sowing（S2D2）;the yield of LK8 ranged from5.06 to 5.77 t·hm^-2,and the low-density and bunch sowing（S2D1）Under the conditions,the yield is the highest.2.High-density and bunch sowing（S2D2）was more favorable for XN538 and low-density and bunch sowing（S2D1）for the population construction and coordinated development of LK8.In terms of the total number of stems and tillers,with the advancement of the growth period of winter wheat,the total number of stems and tillers of XN538 and LK8both increased first and then decreased.At the flowering stage,due to the influence of different population structures,the total number of stems and tillers of XN538 and LK8 was significantly increased compared with that of drilled（S1）treatment.It is D1>D2.In the matter of dry matter accumulation and transport,under different sowing patterns,for XN538,at the flowering stage,the leaf area index and dry matter accumulation were S2>S1,and the dry matter transport efficiency was S2>S1,at the mature stage,the dry matter accumulation is S2>S1;for LK8,at the flowering stage,the leaf area index and dry matter accumulation are S1>S2,and the dry matter transport efficiency is S2>S1,at the mature stage,the dry matter accumulation The quantity is shown as S2>S1.With the increase of planting density,for XN538,at the flowering stage of winter wheat,the leaf area index and dry matter accumulation were D2>D1,and the dry matter transport efficiency was D1>D2,at the mature stage,the dry matter accumulation was expressed as D1>D2;for LK8,under different sowing patterns,with the raise of planting density,at the flowering stage of winter wheat,the leaf area index and dry matter accumulation were D1>D2,and the dry matter transport efficiency was D1>D2,in the mature stage,the dry matter accumulation is D1>D2.Both low-density and bunch sowing（S2D1）could significantly enhance the photosynthesis of XN538 and LK8.At the flowering stage of winter wheat,increase with planting density,the response trend of XN538 and LK8 was the same,and the net photosynthetic rate,stomatal conductance and transpiration rate of flag leaves all decreased significantly,showing that D1>D2.The effects of different seeding methods on leaf net photosynthetic rate,leaf stomatal conductance and transpiration rate of XN538 and LK8 were significantly different,showing S2>S1.The results indicated that under the condition of S2D1,it is more advantageous to improve the stomatal conductance and transpiration rate of winter wheat leaves,which can make CO₂ freely enter and leave winter wheat mesophyll cells,which is more conducive to the assimilation of photosynthetic products of plants.3.Low-density and bunch sowing（S2D1）can significantly reduce the lodging index of different winter wheat varieties.The test showed that under different sowing patterns,for XN538 and LK8,the lodging index decreased significantly,the bending moment did not change significantly,and the breaking moment increased significantly;the plant height and the height of the center of gravity decreased significantly compared with the drilling（S1）treatment,stem thickness and wall thickness increased,stem strength increased,and lodging risk decreased;stem sheath fullness and bending resistance increased significantly,stem non-structural carbohydrate and structural carbohydrate content increased,stem mechanical strength increased,Lodging risk is reduced.Under different planting density levels,for XN538and LK8,increase with planting density,the lodging index increased significantly,the bending moment increased significantly,and the breaking moment decreased significantly;Remarkably decreased;the plumpness and bending resistance of the stem sheath decreased significantly,the content of non-structural carbohydrates and structural carbohydrates in the stem decreased,and the stem was deteriorated.Therefore,low-density and bunch sowing（S2D1）is beneficial to improve the lodging resistance of winter wheat populations of different varieties.Based on this experimental study,in the Guanzhong region of Shaanxi Province,using the seeding pattern of bunch sowing,setting a suitable planting density of450×10⁴ plant·hm^-2 for XN538 and a suitable planting density of 300×10⁴ plant·hm^-2 for LK8 can construct a reasonable winter wheat.It can improve the lodging resistance of winter wheat while increasing the yield,which provides a new idea for the realization of high-yield and high-quality cultivation of winter wheat in Guanzhong region of Shaanxi Province.